someone who is one or all of the following : dishonest, shady, secretive, a player, 'all talk' without following thru, not worthy of trust....in general, a lack of ethics or general morale ie: worthless

Actual meaning- petty, insignificant, someone who is overly concerned with things that really don't matter outside of his or her own mind.

Example: a person could be considered "trifling" if they value money or superficial things that really are not important such as a gold digger or dudes who post handfuls of cash in their hands in a bathroom selfie to impress others when clearly the background of their selfie is a POS college dorm type place they are living in with a broken shower head so it's obvious they are not really rich.

Another version is someone who makes a big deal out of things like not closing the blinds correctly or putting the toilet seat down.

A person can be called trifling as an insult as well because you are saying that they do not matter to anyone else but themselves, you are saying that they are unimportant.

My boss has gotten all worked up about trifling things lately, he posted signs everywhere that if the blinds aren't closed correctly or the air isn't on the exact temperature then you get blasted with some stupid email about it. It seems he really needs to find something in his life worth worrying about.